docs: def make_pawn(self, thing):
          """Make a :class:`Pawn` to represent a :class:`Thing`, store it, and
          return it.
  
          """
          if thing["name"] in self.pawn:
              raise KeyError("Already have a Pawn for this Thing")
          r = self.pawn_cls(
              board=self,
              thing=thing
          )
          self.pawn[thing["name"]] = r
          return r